Phone numbers are frequently reused. For instance, a first user may be associated with the first user. The first user may subsequently receive a new phone number, such that he or she is no longer associated with the first user. For example, the first user may have moved to a location with an area code that is different than the area code of the particular phone number, such that he or she gives up the particular phone number to receive a new phone number with the new area code. As another example, the first user may switch telecommunication companies, and may decide to receive a new phone number instead of retaining the particular phone number in question. Because the particular phone number is now available, it may be assigned to a different, second user, such that the particular phone number is now associated with the second user.
However, the first user may not have informed people who would ordinarily call him or her that his or her phone number has changed. Even if the first user does inform these people, they may forget and/or they may not immediately updated their address books with the first user's new phone number. A caller may thus try to reach the first user by calling the particular phone number, even though it is no longer associated with the first user. Rather than the first user answering the phone call, however, the second user might. This situation can be costly: the caller and/or the second user may incur calling time charges for these phone calls. Furthermore, if the second user receives a large number of phone calls intended for the first user, the second user may become frustrated, and stop answering phone calls that are from people and/or from phone numbers with which the second user is not immediately aware.